So I should run a RO System after water softener for aquarium use?
I got concern about the high Sodium for planted tank and fish

The membrane blocks the sodium same as it does the calcium, the difference is the occurrence of scaling that blocks (plugs up) the membrane. Having a membrane flush bypass and installing after the whole house softener the membrane will last much longer because salt ions are much easier to flush off the membrane than the calcium is. Based on conductivity tests and a sample tested at a water lab I know the sodium is blocked by the RO membrane. Anything else in the way of debate regarding sodium ions in a freshwater system I'll leave to others.

Quote:

Originally Posted by Diana

Check the RO unit you want. It is my understanding that the RO membranes wear out faster if they are processing water that is high in calcium, so installing the RO after a sodium exchange water softener is a good idea.

Exactly what I did and why with no regrets.

With multiple tanks scattered throughout my home a central system hard piped wasn't for me. Wife didn't want it in the mud room either.

Mine was a well water quality issue and I gained a tremendous amount of my information on eBay trying to decide what I wanted in a system. The vendors are indeed a great source of info trying to sell products. Ask questions and the answers fly to your inbox.

My needs (I felt) included a 100g reserve in storage. I installed the system in the detached garage (keeps my wife happy as its not in the laundry room).
Set it up down stream of the whole house Kinetco system (salt regen) water softener. Insulated the tank with black rubber leaving a 2 1/2" gauging gap marked at 5gal. intervals. Through a bulk head fitting on top is installed a 400 watt heater for Florida's short winter and an air pump. A float switch in the storage tank and pressure switch in the supply line shuts off the supply booster pump and supply water. The product water discharge pump is a Surflo Demand Pump - 115v with 1/2 inch male threads, 45 p.s.i. and 3.3 gallons per minute rated discharge anchored to the floor under the laundry sink.

The RO is a 6 stage. Wall mounted above the laundry sink with the waste water fed to a flower bed outside the shop wall rather than the sink drain.
With the booster pump on the supply side I get almost a 1:1 ratio taking the 191 (or more) TDS input to 1 or 2ppm TDS discharge. The booster pump gets credit for the increased ratio pushing 80-85 psi system pressure (needle bounces). The gauge is between the last filter can and the membrane housing, right in front of the pump.

The final stage UV sterilizer gives me peace of mind on my storage water after reading concerns about bacteria content in well supplied systems and also possible bacteria build up in the filters themselves.

The water storage tank (105g) is from a local commercial supply and was just over $150.00. Food grade with a vented and threaded lid along with the lower bulkhead that's connected to the discharge pump.
Drinking water safe hose and a valved nozzle are used to transport water to the tanks. (yes I drag a hose)

I really like the Surflo demand pump with the pressure switch built in for filling my tanks simply for the fact it shuts off rather than running dead headed is why I bought it. I'll drain and clean a tank then move to the next one without a trip out to shut off the supply pump.

Another thought in the design of the system was rather than allowing it to continuously refill the reservoir I prefer to shut the water supply off once it's filled and turn off the power supply switch. This bottles up my RO filter wet between uses and removes power from all devices. Also it forces me walk out and manually restart the reservoir fill. Flushing the membrane surface after every 100 gallons of produced product water by using a bypass flush before the reservoir is refilled. It makes me do my maintenance cycle on the membrane doing it this way LOL. I have only replaced one membrane in three years of use.
Currently maintaining >840g in total aquarium volume in house.

More cost on some of the components used but felt that was warranted.
The membrane and housing are SpectraPure brand.